John b



(No Model.)

Y J B DAVIDS METHOD OF PROMOTING GOMBUSTIONIN FURNACES.

Patented May 8; 1894.

[we/2% HQQM'OAL boilers of steam vessels.

NITED STATES EATENT OFFICE...

JOHN B. DAVIDS, OF DARTMOUTH, MASSACHUSETTS, ASSIGNOR TO E. M.

CHISHOLM DAVIDS, OF SAME PLACE.

METHOD OF PROMOTING COMBUSTION IN FURNACES.

, SPECIFICATION forming part of Letters Patent No. 519,325, dated May 8, 1894:.

Application filed April 29, 1893.

Serial No. 472,391. (No model.)

To aZZ whom it may concern.-

Be it known that I, JOHN B. DAVIDS, a citizen of the United States, residing at (North) Dartmouth, in the county of Bristol and State of Massachusetts, have invented certain new and useful Improvements in Methods of Pro moting Combustion in Furnaces, of which the following is a specification.

This invention relates more particularly to methods of promoting combustion, under the The method ordinarily employed, of promoting combustion under such boilers, is to construct the fire room, so that it can be tightly closed, and

forcing air into said room, and then through the fire, in such quantity as to give the required combustion. This method, makesit impossible for the firemen to sustain life in such room, longer than a few minutes at a time, on account of the condensed air and the great heat.

The object of this invention, is to render the firing of such boilers, more endurable, and less risky to the lives of the firemen.

The'ac'companying drawings illustrate my invention, in which-- Figure 1 represents a front elevation of a smoke stack, boiler, and firebox, provided with my improvements, and having a portion of the fire-box broken away, to more fully show a portion of the construction. Fig. 2. represents a side elevation of the same showing the smoke stack and fire-box in perpendicular longitudinal section.

Similar letters refer to similar parts in both the views.

a,represents a smoke stack to a boiler having an air-tight chamber 0, around the outside of its base.

d, represents a circular partition, secured to the bottom of the chamber 0, and extending nearly to the top of said chamber.

e, represents tubes of varyiuglengths which are secured in that portion of thewall of the smoke stack inclosed by the chamber a, and extend upward along the inside of the same; preferably having their ends h, inclined inward toward the center of the flue.

g, represents a pipe, resting on the chamber c, and provided with the holes 3, near its base, and sufficiently large in diameter, to

leave an air-space Z, between it and the outhaving its end 0, projecting under the grate.

of the fire-boxy", where, it is provided with a series of perforations p.

Z, represents an air-pipe, branching from the pipe 70, and leading into the chamber 0. The pipe Z, is supplied with the valve m, and the pipe is, is supplied with the valve n, located between the junction of the pipes It, andZ, and the fire-boxf. The pipe Z0, is further supplied with the openings g, which are adapted to be closed by the slide 1'.

In operation, air is forced through the pipes Z6, and Z, by an air pump or other suitable means. The air which passes through the pipe Z, enter the chamber 0, and passes thence into the tubes e, and out, at their upper ends. The strong blast of air, issuing from the upper ends of the tubes e, causes a partial vacuum below them, which the air, still below, rushes to fill, and thus a strong upward current of air is created in the stack, and a strong draft is obtained. The draft is further assisted by the air issuing from the perforated end 0, of the pipe is. When coal is added to the fire, the blast from the perforation p, is shut off by the valve 'n, in order to prevent the flames from issuing from the door of the firebox, When no increased draftis desired, the valves m, and n, are both closed.

When my improvement is used in connection with the boilers of a steam vessel, the openings q, in the pipe 70, may be opened, so as to admit a supply of air to the bottom of the fire room, and thus materially lessen its temperature.

The circular partition d, serves to distribute the air entering the chamber 0, from the pipe.

1', and having the branch 0, provided with the I00 valve 42, and perforations 9, extending into tween said points, or shut off from any or all the fire box under the fire; and having the branch Z, provided with the valve m, extending into the chamber 0, surrounding the base of the smoke stack; whereby the blast of air through said pipe, may he directed wholly below the fire, or wholly into the smoke stack, or wholl x into the fire room, or divided beof said points, as and for the purpose speciro fied.

JOHN B. DAVIDS.

WVitnesses:

H; W. MASON, JAMES C. HITCH. 

